grind down

present singular third person grinds down · participle present grinding down · participle past ground down · past ground down

1. transitiveTo make something hard smaller and smoother by gradually rubbing off tiny bits; to wear down by grinding action.

   The old dog's teeth had been ground down by constant use.

2. idiomatictransitiveTo weaken someone's morale over a long period.

   Djokovic broke twice in each of the opening two sets, dismantling 6ft 8in Anderson's service game and grinding him down in the rallies.

   2018 July 15, Jonathan Jurejko, “Novak Djokovic wins fourth Wimbledon by beating Kevin Anderson”, in BBC Sport

   1 more example

   I'm living in a world where I don't really fit Every day walking through the same old shit I'm gonna get my gun, gonna get prepared I'm not impressed and I'm not scared Don't let the bastards grind you down! Don't let them grind you down! Don't let the bastards grind you down! Don't let them grind you down!

   1997, The Toasters, Don't Let the Bastards Grind You Down